10:19am CDT Vortex: 947mb, 6kts of sfc wind; Single 18nm closed eye; Higher flight winds
Posted by Chris in Tampa on 8/25/2017, 12:08 pm
Previously, there were concentric eyes for a bit. This could mean even more than expected strengthening. Already, winds are even higher now at flight level:

30 second flight level wind: 109 kts (125.4 mph)
10 second flight level wind: 112 kts (128.9 mph)
10 second estimated surface wind: 95 kts (109.3 mph)

Meanwhile, sonde dropped in NE eyewall...

925mb level, 1,345 ft up, a momentary wind of 142 mph.

Lower in altitude, at 937mb level, 146mph.

Surface wind at this location, 107 mph.

Particular sonde:
http://hurricanecity.com/recon/recon.cgi?basin=al&year=2017&product=sonde&storm=Harvey&mission=17&agency=AF&ob=08-25-1519-35-969-127-93

These are not 1 minute sustained. As the sonde falls from the plane, these wind are recorded. They are momentary.

While the data might not support higher than 110mph right this moment, perhaps, the data does indicate than in a very short amount of time, surface winds will be higher.

I'm not so sure they don't use this sometimes though:

Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding:
- Lowest 150m: 157 gpm - 7 gpm (515 geo. feet - 23 geo. feet)
- Wind Direction: 100° (from the E)
- Wind Speed: 110 knots (127 mph)

In some way. Perhaps they use a percentage. But it is clear, Harvey is still strengthening and these winds we are seeing higher up are starting to increase a lot.


Previous highest in E quad, 30s flight:
98 kts (112.8 mph)

Just now in the NE, 30s flight:
109 kts (125.4 mph)


Previous highest in E quad, 10s flight:
104 knots (119.7 mph)

Just now in the NE, 10s flight:
112 knots (128.9 mph)


A little over two hours difference in those.



URNT12 KNHC 251528
VORTEX DATA MESSAGE   AL092017
A. 25/15:15:20Z
B. 26 deg 45 min N
 096 deg 05 min W
C. 700 mb 2631 m
D. 94 kt
E. 325 deg 7 nm
F. 065 deg 102 kt
G. 320 deg 11 nm
H. 947 mb
I. 11 C / 3055 m
J. 17 C / 3049 m
K. 13 C / NA
L. CLOSED
M. C18
N. 12345 / 07
O. 0.02 / 1.25 nm
P. AF305 1709A HARVEY             OB 31
MAX OUTBOUND AND MAX FL WIND 112 KT 055 / 15 NM 15:20:00Z
CNTR DROPSONDE SFC WIND 295 / 6 KT



Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 25th day of the month at 15:28Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF97-5305
Storm Number & Year: 09 in 2017
Storm Name: Harvey (flight in the North Atlantic basin)
Mission Number: 17
Observation Number: 31
A. Time of Center Fix: 25th day of the month at 15:15:20Z
B. Center Fix Coordinates: 26°45'N 96°05'W (26.75N 96.0833W)
B. Center Fix Location: 104 statute miles (167 km) to the ENE (57°) from Brownsville, TX, USA.
C. Minimum Height at Standard Level: 2,631m (8,632ft) at 700mb
D. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 94kts (~ 108.2mph)
E. Location of the Estimated Maximum Surface Wind Inbound: 7 nautical miles (8 statute miles) to the NW (325°) of center fix
F. Maximum Flight Level Wind Inbound: From 65° at 102kts (From the ENE at ~ 117.4mph)
G. Location of Maximum Flight Level Wind Inbound: 11 nautical miles (13 statute miles) to the NW (320°) of center fix
H. Minimum Sea Level Pressure: 947mb (27.97 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 11°C (52°F) at a pressure alt. of 3,055m (10,023ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 17°C (63°F) at a pressure alt. of 3,049m (10,003ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 13°C (55°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Closed
M. Eye Shape & Diameter: Circular with a diameter of 18 nautical miles (21 statute miles)
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Levels (sfc and flt lvl centers are within 5nm of each other): Surface and 700mb
O. Navigational Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1.25 nautical miles

Remarks Section:
Maximum Outbound and Flight Level Wind: 112kts (~ 128.9mph) which was observed 15 nautical miles (17 statute miles) to the NE (55°) from the flight level center at 15:20:00Z
Dropsonde Surface Wind at Center: From 295° at 6kts (From the WNW at 7mph)



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10am CDT Friday: 110mph; 947mb; NW at 10mph - Chris in Tampa, 8/25/2017, 11:00 am
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